Hello,
I recently built a couple of these however one of them doesn't have any output signal. For reference I've tried swapping op amps ( currently using one of Capi's prebuilt 2520 clones) According to the guide c7 should be 120uf 50v nichicon however I received a 100uf 63v kingtronics gf2323 PET capacitor instead in the one that isn't working- besides that I've triple checked that all the resistor and capacitor orientations are the same/ correct.
I de-soldered the output transformer leads of the non working preamp and compared it to the others I have uninstalled and the non working card's output was in the expected ranges. For reference:
Orange & Yellow - 11.4 ohms
Green & Blue- 11.6 ohms
Violet & Gray- 11.2 ohms
Brown & red- 11.7 ohms
After ensuring both have the same gain settings (stepped input middle , max output attenuator) and the phantom is off-
without uninstalling the input transformers and comparing eachother unpowered, I did notice a discrepancy however
Good Installed input:
Pin 1 & 3 -12 ohms
Pin 2 & 4- 11.5 ohms
Pin 5 & 8- 1.89k
Non Working 312 installed input transformer:
Pin 1 & 3- 11.5 ohms
Pin 2 & 4- 11.5 ohms
Pin 5 & 8- 9.8 Ohms
Any further troubleshooting I can try here? Pretty stumped
